This invention relates to a heel and sole structure for shoes and boots that makes it easy to replace the worn-out wear layer of a heel or sole with a new wear layer in a quick and easy manner any number of times without the use of glue or nails to attach the new wear layer to the heel or sole.
It is known that heels and soles of shoes and boots wear out more rapidly than the other portions of the shoes or boots. Heretofore, repair has involved replacement of the worn-out layer using conventional methods of either gluing, sewing or nailing of the new wear layer to the soles or heels of the shoes or boots. This procedure is time consuming and rather costly. The repair work usually requires the use of hammer and nails and some other tools. The prior art repair work takes some time and cannot be done quickly. Generally, the shoes or boots must be left for some time with the person who is to do the repair work. The repair work is seldom done while the customer waits. There are numerous prior art patents relating to repair of shoes and boots, but there are only a few patents which have any resemblance to the present invention. None of the prior art patents disclose the full advantageous features of this invention. For example, U.S. Pat. No. 684,515 describes a detachable heel with flat-headed projections that would engage in some key-hole slots in the fixed layer of the heel, and a lug at the free end of a fixed spring that would engage into a hole in the detachable layer to hold it in a fixed position. A similiar structure was registered under U.S. Pat. No. 1,270,523 with the difference that a fixed transverse flange along the inner edge of the fixed heel is used to prevent the detachable layer from sliding out of its position. Another use of key-hole slots for detachable heels is found in U.S. Pat. No. 1,463,427, along with the suggestion of using struck-up parts in adjoining metal plates for holding the relative position of the wear-layer against the heel
U.S. Pat. Nos. 2,115,050 and 2,115,350 suggest the use of a mounting member, or fixed layer, containing a plurality of sockets with key-hole openings that have beveled small portions for engaging flaring heads of coupling pins attached to the removable wear layer. As a mechanism for preventing disengagement of the wear layer, these Patents suggest the use of an upwardly projected lip on the detachable heel that would engage in a corresponding recess or opening inside the mounting member. Finally, U.S. Pat. No. 2,206,898 claims the idea of using a detachable tread heel, attached to a plate provided with a number of outwardly extended elements which are adapted to be engaged in corresponding open recesses in the fixed heel, and a central locking mechanism, composed of a leaf spring secured to the plate and a free end urged outwardly of the plate into a corresponding recess in the lower surface of the base heel
Common disadvantages of the above referenced patents are: (a) necessity of using relatively thick layers of material, either in the wear layer or in the fixed (mounting) layer, for accomodating the locking mechanism and, (b) the practical difficulties of inserting and removing the detachable layer. In particular, regardless of the mechanism used to keep the wear layer in its place, after a period of usage and subjection to pressure due to weight bearing, the wear layer adapts so tightly to the heel or sole structure that its removal requires considerable force for displacement. None of the referenced patents provides a means to ease this phase of replacement.